Detailed Description of the Invention
Technical Field
[0001] The present invention relates to a method and apparatus in which a User Equipment
(UE) performs Channel Status Information (CSI) reporting to a Node B in a cellular
radio communication system.
Background Art
[0002] A mobile communication system has evolved to a high-speed, high-quality wireless
packet data communication system in order to provide data services and multimedia
services in addition to voice-based services.
[0003] Telecommunications Standards Institutes, such as 3rd Generation Partnership Project
(3GPP), 3rd Generation Partnership Project 2 (3GPP2), and Institute of Electrical
and Electronics Engineers (IEEE), have developed various mobile communication standards,
such as High Speed Packet Access (HSPA), Long Term Evolution (LTE), Long Term Evolution
Advanced (LTE-A), High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and
IEEE 802.16e, to provide high-speed, high-quality packet data services.
[0004] In a LTE system which is a representative example of a broadband wireless communication
system, Downlink adopts an Orthogonal Frequency Division Multiplexing (OFDM) scheme,
and Uplink adopts a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme.
The multiple access scheme allocates and manages resources such that time-frequency
resources to carry data or control information for individual users do not overlap,
that is, such that orthogonality between users is ensured to thereby separate data
or control information according to users.
[0005] One of important technologies for providing high-speed radio data services in a broadband
wireless communication system is to support a scalable bandwidth. For example, a system
transmission band of a LTE system can have various bandwidths, such as 20MHz, 15MHZ,
10MHz, 5MHz, 3MHz, and 1.4MHz, and service providers can select a specific bandwidth
from among such various bandwidths to provide a service. Also, there are various kinds
of User Equipments (UEs) from UEs supporting a bandwidth of maximally 20MHz to UEs
supporting a bandwidth of minimally 1.4MHz. Particularly, a LTE-A system can provide
a broadband service that covers a bandwidth of maximally 100MHz through Carrier Aggregation
(CA) servicing UEs through a plurality of Component Carriers (CCs).
[0006] A LTE and LTE-A system can support both a Frequency Division Duplex (FDD) scheme
and a Time Division Duplex (TDD) scheme. The FDD scheme uses separate frequencies
for uplink and downlink, whereas the TDD scheme divides transmission and reception
of uplink signals and downlink signals in the time domain while using a common frequency
for uplink and downlink.
[0007] However, a typical mobile communication system supporting CA has limitation that
the same duplex scheme should be applied to CCs. That is, only CCs using the FDD scheme
or only CCs using the TDD scheme are aggregated. If CCs configured for a UE use different
duplex schemes, the UE may perform uplink transmission at different timings according
to the CCs. Accordingly, for a CA system in which a cell using an FDD scheme and a
cell using a TDD scheme are aggregated and operated, a technology for enabling a UE
to effectively report Channel Status Information (CSI) to a node B is needed.
[0008] EP 2 597 799 A2 discloses a method of performing a CSI report by a UE, according to which, if CSI
reports of a plurality of serving cells (PCell, SCell) collide with each other in
a subframe, one or more CSI reports having lower priorities are dropped. If CSI reports
of different serving cells having a same priority collide with each other in the corresponding
subframe, CSI reports of one or more serving cells other than one serving cell having
the lowest index are dropped.
[0009] The
3GPP draft "Joint TDD-FDD Carrier Aggregation", R1-134274, discloses that for periodic CSI reporting, the priority of CSI reports is based
on PUCCH reporting types and serving cell index, and that when the PCell is TDD, restrictions
could be placed on the CQ1/PM1 reporting period of a FDD SCell to prevent frequent
dropping of CSI reports.
[0010] EP 2 562 949 A2 discloses transmitting UCI (uplink control information) by user equipment in a carrier
aggregation system.
Disclosure
Technical Problem
[0011] The invention is solely defined by the appended claims. In the following, references
to embodiments not falling within the scope of the claims are to be understood as
examples useful for understanding the invention.
[0012] The present disclosure provides a method and apparatus in which a User Equipment
(UE) reports Channel Status Information (CSI) to enable a Node B to efficiently transmit
downlink data in a radio communication system.
[0013] The present disclosure provides a method and apparatus in which a UE efficiently
reports CSI in a communication system supporting Carrier Aggregation (CA).
[0014] The present disclosure provides a method and apparatus in which a UE reports CSI
to a node B in a communication system supporting CA of Component Carriers (CCs) of
different duplex modes.
[0015] The present disclosure provides a method and apparatus in which a node B decides
a CSI transmission period for a secondary cell of a UE when CA has been configured
between cells of different duplex modes.
[0016] The present disclosure provides a method and apparatus in which a UE periodically
transmits CSI of a secondary cell through a primary cell when CA has been configured
between cells of different duplex modes.
Technical Solution
[0017] The invention is solely defined by the appended claims. In the following, references
to embodiments not falling within the scope of the claims are to be understood as
examples useful for understanding the invention.
[0018] In accordance with an aspect of exemplary embodiments of the present invention, there
is provided a method of receiving channel status information (CSI) in a cellular radio
communication system including: configuring carrier aggregation (CA) between a primary
cell of a first duplex mode and a secondary cell of a second duplex mode with respect
to a user equipment (UE), and deciding a CSI transmission period of the secondary
cell based on a first group of CSI transmission periods defined for the first duplex
mode; and transmitting information about the decided CSI transmission period to the
UE.
[0019] In accordance with another aspect of exemplary embodiments of the present invention,
there is provided a method in which a user equipment (UE) reports channel state information
(CSI) in a cellular radio communication system including: receiving configuration
information for configuring carrier aggregation (CA) between a primary cell of a first
duplex mode and a secondary cell of a second duplex mode, from a Node B; receiving
information representing a CSI transmission period for periodic CSI reporting of the
secondary cell, from the node B; and reporting CSI of the secondary cell to the node
B according to the CSI transmission period, wherein the CSI transmission period of
the secondary cell is decided based on a first group of CSI transmission periods decided
for the first duplex mode.
[0020] In accordance with another aspect of exemplary embodiments of the present invention,
there is provided a node B of controlling channel status information (CSI) reporting
in a cellular radio communication system including: a controller adapted to configure
carrier aggregation (CA) between a primary cell of a first duplex mode and a secondary
cell of a second duplex mode with respect to a user equipment (UE), and to decide
a CSI transmission period of the secondary cell based on a first group of CSI transmission
periods defined for the first duplex mode; and a transmitter adapted to transmit information
about the decided CSI transmission period to the UE.
[0021] In accordance with another aspect of exemplary embodiments of the present invention,
there is provided a user equipment (UE) of reporting channel status information (CSI)
in a cellular radio communication system including: a receiver adapted to receive
configuration information for configuring carrier aggregation (CA) between a primary
cell of a first duplex mode and a secondary cell of a second duplex mode, from a node
B, and to receive information representing a CSI transmission period for periodic
CSI reporting of the secondary cell from the node B; and a transmitter adapted to
report CSI of the secondary cell to the node B according to the CSI transmission period,
wherein the CSI transmission period of the secondary cell is decided based on a first
group of CSI transmission periods decided for the first duplex mode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022]
FIG. 1 shows a basic structure of an uplink time-frequency resource area in a Long
Term Evolution (LTE) system;
FIG. 2 shows an example of a system configuration of a LTE-Advanced (LTE-A) system
supporting Carrier Aggregation (CA);
FIG. 3 shows a structure of a special subframe of a Long Term Evolution Time Division
Duplex (LTE TDD) system;
FIG. 4 is a view for describing timing for an uplink report when cells to which CA
is applied use different duplex schemes;
FIGS. 5A and 5B show an example of operation when a CSI transmission period is 2 subframes,
according to an embodiment of the present disclosure;
FIGS. 6A and 6B show another example of operation when a CSI transmission period is
2 subframes, according to an embodiment of the present disclosure;
FIG. 7 shows an example of operation when a CSI transmission period is 5 subframes,
according to an embodiment of the present disclosure;
FIGS. 8A and 8B show an example of operation when a CSI transmission period is 32
subframes, according to an embodiment of the present disclosure;
FIGS. 9A and 9B show an example of operation when a CSI transmission period is 64
subframes, according to an embodiment of the present disclosure;
FIGS. 10A and 10B shows an example of operation when a CSI transmission period is
128 subframes, according to an embodiment of the present disclosure;
FIG. 11 is a flowchart illustrating a method of setting a CSI transmission period,
according to an embodiment of the present disclosure;
FIG. 12 is a flowchart illustrating a method of setting a CSI transmission period,
according to another embodiment of the present disclosure;
FIG. 13 is a flowchart illustrating a method of setting a CSI transmission period,
according to another embodiment of the present disclosure;
FIG. 14 is a flowchart illustrating a method in which a User Equipment (UE) reports
CSI, according to an embodiment of the present disclosure;
FIG. 15 shows a configuration of a UE transmission apparatus according to an embodiment
of the present disclosure; and
FIG. 16 shows a configuration of a Node B reception apparatus according to an embodiment
of the present disclosure.
Best Mode
[0023] Hereinafter, embodiments of the present disclosure will be described in detail with
reference to the accompanying drawings. In the following description, if it is determined
that detailed descriptions for related, well-known functions or configurations make
the subject matter of the present disclosure obscure unnecessarily, the detailed descriptions
will be omitted. Also, although terms used in the present disclosure were selected
as terminology used in the present disclosure while considering the functions of the
present disclosure, they may vary according to a user's or operator's intentions,
judicial precedents, and the like. Hence, the terms must be defined based on the contents
of the entire specification, not by simply stating the terms themselves.
[0024] The embodiments of the present invention will be described by employing Evolved Universal
Mobile Telecommunications System Terrestrial Radio Access (E-UTRA) (or, called "LTE")
or Advanced E-UTRA (or, called "LTE-A"). However, the present disclosure is not limited
to such specific systems, and the embodiments of the present invention can also be
applied to various communication systems having similar technical background and/or
channel type. The invention is solely defined by the appended claims. In the following,
references to embodiments not falling within the scope of the claims are to be understood
as examples useful for understanding the invention.
[0025] In this specification, a Node B (NB), which is an entity to allocate resources to
User Equipments (UEs), may be a eNode B (eNB), a Base Station (BS), a wireless access
unit, a base station controller, or a node on a network. Also, a UE may be a Mobile
Station (MS), a cellular phone, a smart phone, a computer, or a multimedia system
that can perform a communication function.
[0026] FIG. 1 shows a basic structure of an uplink time-frequency resource area in a Long
Term Evolution (LTE) system. An uplink (UL) means a radio link through which a UE
can transmit data or control signals to a NB, and a downlink (DL) means a radio link
through which a NB can transmit data or control signals to a UE.
[0027] Referring to FIG. 1, in a 2Dimentional (2D) radio resource area, the horizontal axis
represents a time domain, and the vertical axis represents a frequency domain. In
the time domain, a minimum transmission unit may be a Single Carrier Frequency Division
Multiple Access (SC-FDMA) symbol, a N
symb number 102 of SC-FDMA symbols may be grouped to configure a slot 106, two slots may
be grouped to configure a subframe 105, and 10 subframes may be grouped to configure
a radio frame 107. The length of the slot 106 may be 0.5ms, the length of the subframe
105 may be 1.0ms, and the length of the radio frame 107 may be 10ms. In the frequency
domain, a minimum transmission unit is a subcarrier.
[0028] In the time-frequency domain, a basic unit of a resource may be a Resource Element
(RE) 112, and each RE 112 may be defined by a SC-FDMA symbol index and a subcarrier
index. A resource block (RB) (also, referred to as a Physical Resource Block (PRB))
108 may be defined by a N
symb number of successive SC-FDMA symbols 102 in the time domain and a N
RBSC number of successive subcarriers 110 in the frequency domain. Accordingly, a RB
108 may be configured with a N
symb x N
RBSC number of REs 112. Generally, a minimum transmission unit of data may be a RB,
and a system transmission band may be configured with a total N
RB number of RBs. Also, a total system transmission band may be configured with a total
N
RB x N
RBSC number of subcarriers 104. In a LTE system, generally, N
symb = 7 and N
RBSC = 12. However, in some cases, N
symb and N
RBSC may be set to other values.
[0029] The LTE system may use schemes, such as an Adaptive Modulation and Coding (AMC) scheme
and a Channel Sensitive Scheduling (CSS) scheme, in order to improve transmission
efficiency. When the AMC scheme is used, a transmitter can adjust an amount of data
to transmit according to a channel status. That is, if a channel status is poor, the
transmitter may decrease an amount of data to transmit to adjust probability of reception
errors to a desired level. Also, if a channel status is good, the transmitter may
increase an amount of data to transmit to adjust probability of reception errors to
a desired level, while effectively transmitting a large amount of information. When
a CSS-based resource management scheme is used, the transmitter may provide a service
selectively to a user having an excellent channel status from among many users so
as to be able to increase radio system capacity of a mobile communication system,
compared to a method of allocating a channel and providing a service to each user.
Such an increase in capacity is called a Multi-user Diversity (MuD) gain. In summary,
the AMC scheme and the CSS scheme are to receive a feedback about partial Channel
Status Information (CSI) from a receiver, and to apply an appropriate modulation and
coding scheme at a time determined to be a most efficient time.
[0030] If the AMC scheme is used together with a Multiple Input Multiple Output (MIMO) scheme,
a function of deciding the number (or rank) of spatial layers to transmit signals,
precoding, etc. can be provided. In this case, the AMC scheme may use MIMO to decide
what number of transmission layers are to be used, instead of considering only a coding
rate and a modulation method, in order to decide an optimal data rate.
[0031] In order to support the AMC scheme, a UE may need to perform operation of reporting
CSI to a NB. The CSI may include at least one of a Channel Quality Indicator (CQI),
a Precoding Matrix Indicator (PMI), and a Rank Indicator (RI). The CQI may represent
a Signal to Interference and Noise Ratio (SINR) for the wideband or subband of a system.
The CQI may be expressed in the form of a Modulation and Coding Scheme (MCS) for satisfying
generally required data reception performance. The PMI may provide precoding information
required for a NB to transmit data through multiple antennas in a system supporting
MIMO. The RI may provide rank information required for a NB to transmit data through
multiple antennas in a system supporting MIMO. The CSI may be information which a
UE provides to a NB in order to help determination on scheduling of the NB. The NB
may determine information, such as a MCS, precoding, a rank, and the like, which is
applied for actual data transmission, based on the CSI.
[0032] The UE may periodically transmit CSI at regular time intervals according to a pre-appointment
with the NB. This is called "periodic CSI reporting". The NB may inform the UE of
control information (for example, a CSI transmission period, a CSI transmission resource,
etc.) required for the "periodic CSI reporting" of the UE, through signaling. For
the "periodic CSI reporting", the UE may transmit CSI to the NB, basically, through
a Physical Uplink Control Channel (PUCCH). However, there may be an exception that
the UE needs to perform transmission through a Physical Uplink Shared Channel (PUSCH)
which is a channel for uplink data transmission, at the time when CSI has to be transmitted
for "Periodic CSI reporting". In this case, the UE may multiplex CSI with uplink data
to transmit to the NB through the PUSCH.
[0033] Differently from "periodic CSI reporting", the NB may request the UE to perform "aperiodic
CSI reporting", as necessary. The NB may transmit "control information requesting
aperiodic CSI reporting" to the UE through a control channel for scheduling uplink
data of the UE. The UE may receive a request for "aperiodic CSI reporting" through
the "control information requesting aperiodic CSI reporting", and may report CSI to
the NB through the PUSCH.
[0034] The LTE system adopts a Hybrid Automatic Repeat reQuest (HARQ) scheme of re-transmitting,
when a decoding failure occurred at a UE or a NB upon data transmission, the corresponding
data in a physical layer. In the HARQ scheme, when a receiver fails to accurately
decode data, the receiver may transmit HARQ NECK (Negative Acknowledgement) which
is information of informing a decoding failure to a transmitter so that the transmitter
can retransmit the corresponding data in the physical layer. Then, the receiver may
combine data re-transmitted from the transmitter with the data subject to the decoding
failure to increase data reception performance. Meanwhile, if the receiver has accurately
decoded data, the receiver may transmit HARQ ACK (Acknowledgement) which is information
of informing a decoding success to the transmitter so that the transmitter can transmit
new data.
[0035] Control information, such as HARQ ACK/NACK and CSI, which is fed back from the UE
to the NB, is called Uplink Control Information (UCI). In the LTE system, the UCI
may be transmitted to the NB through the PUCCH which is an uplink control channel
dedicated to control information, or the UCI may be multiplexed with uplink data and
then transmitted to the NB through the PUSCH which is a physical channel for uplink
data transmission.
[0036] One of important factors for providing a high-speed radio data service in a broadband
radio communication system is to support a scalable bandwidth. For example, a system
transmission band of a LTE system has various bandwidths of 20MHz, 15MHz, 10MHz, 5MHz,
3MHz, 1.4MHz, etc., and service providers select a desired bandwidth from the various
bandwidths to provide a service. Also, a UE supports a bandwidth of maximally 20MHz
or a bandwidth of 1.4MHz, according to its kind.
[0037] A LTE-A system requires a wider bandwidth than the LTE system for high-speed data
transmission. Also, the LTE-A system needs to provide backward compatibility with
LTE UEs, and the LTE UEs should be able to access the LTE-A system to receive a service
from the LTE-A system. For this, the LTE-A system divides an entire system band into
component carriers (CCs) or subbands of a bandwidth that a LTE UE can transmit or
receive, and combines several CCs to provide a service to each LTE UE. The LTE-A system
transmits data for each CC, and performs a transmission/reception process of the typical
LTE system for each CC to thereby support high-speed data transmission. As such, the
LTE-A system uses a CA scheme of aggregating LTE carriers to provide a broadband service
through a bandwidth of maximally 100MHz.
[0038] FIG. 2 shows an example of a system configuration of a LTE-A system supporting CA.
[0039] Referring to FIG. 2, a NB 202 may support aggregation of two CCs, that is, CC#1 and
CC#2, wherein CC#1 may be configured with a frequency f1, and CC#2 may be configured
with a frequency f2 that is different from the frequency f1. The CC#1 and CC#2 may
be included in the NB 202. The NB 202 may provide coverages 204 and 206 corresponding
to the respective CC#1 and CC#2. In the LTE-A system supporting CA, data transmission
and control information transmission for supporting data transmission may be performed
for each corresponding CC. In the present specification, the term "cell" is used as
the same meaning as a CC, unless it clearly dictates otherwise. The system configuration
shown in FIG. 2 can be applied to uplink CCs, as well as to downlink CCs.
[0040] In a CA system, each CC may be classified into a primary cell Pcell or a secondary
cell Scell. The Pcell may provide a basic radio resource to a UE, and means a basic
cell in which a UE performs operation, such as initial access and handover. The Pcell
may be configured with a downlink primary frequency (or, referred to as a Primary
Component Carrier (PCC)) and an uplink primary frequency. The UE may transmit UCI
including HARQ ACK/NACK or CSI, which is fed back to the NB, through PUCCH, wherein
the PUCCH can be transmitted only through the Pcell. Meanwhile, the Scell may provide
an additional radio resource to a UE, and may be configured with a downlink secondary
frequency (or, referred to as a Secondary Component Carrier (SCC)) and an uplink secondary
frequency, or only with a downlink secondary frequency.
[0041] The LTE and LTE-A system can support an Frequency Division Duplex (FDD) scheme and
a Time Division Duplex (TDD) scheme for each cell. The FDD scheme uses different frequencies
for an uplink and a downlink, whereas the TDD scheme uses a common frequency for both
an uplink and a downlink, but divides transmission and reception of uplink signals
and downlink signals in the time domain. The LTE and LTE-A system distinguishes and
transmits an uplink or downlink signal for each subframe based on the TDD scheme.
Accordingly, the LTE and LTE-A system may equally allocate subframes for an uplink/downlink
in the time domain, allocate more subframes to the downlink, or allocate more subframes
to the uplink, according to the traffic loads of the uplink and downlink.
[0042] The following Table 1 shows TDD uplink-downlink (UL-DL) configurations defined in
the LTE standard.
[Table 1]
Uplink-downlink configuration |
Subframe number |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
0 |
D |
S |
U |
U |
U |
D |
S |
U |
U |
U |
1 |
D |
S |
S |
S |
D |
D |
S |
U |
U |
D |
2 |
D |
S |
U |
D |
D |
D |
S |
U |
D |
D |
3 |
D |
S |
U |
U |
U |
D |
D |
D |
D |
D |
4 |
D |
S |
U |
U |
D |
D |
D |
D |
D |
D |
5 |
D |
S |
U |
D |
D |
D |
D |
D |
D |
D |
6 |
D |
S |
U |
U |
U |
D |
S |
U |
U |
D |
[0043] As shown in Table 1, each of 10 subframes configuring a radio frame may operate as
one of "D", "U", and "S" according to an uplink-downlink configuration defined by
a NB. Herein, "D" represents a subframe set for downlink transmission, "U" represents
a subframe set for uplink transmission, and "S" represents a special subframe configured
with a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), and an Uplink Pilot
Time Slot (UpPTS). In the DwPTS, downlink control information can be transmitted,
like in a general downlink subframe, and if the length of the DwPTS is sufficiently
long according to the configuration of the special subframe, downlink data can also
be transmitted. The GP may be used to enable transition from a downlink to an uplink,
and the length of the GP may be decided according to a network setting and the like.
The UpPTS may be configured with one or two SC-FDMA symbols, and the UpPTS may be
used to transmit a Sounding Reference Signal (SRS) of a UE required for a NB to estimate
an uplink channel status, or to transmit a random-access preamble of a UE for random
access.
[0044] FIG. 3 shows a structure of a special subframe of a Long Term Evolution Time Division
Duplex (LTE TDD) system.
[0045] Referring to FIG. 3, the special subframe may have a length of 1ms, like a general
subframe. According to a special subframe configuration given by a NB, DwPTS 301 may
be configured with 3 to 12 OFDM symbols, UpPTS 303 may be configured with 1 or 2 SC-FDMA
symbols, and GP 302 may be configured with the remaining time period resulting from
subtracting the length of the DwPTS 301 and the UpPTS 303 from 1ms. The special subframe
may be set to a location of Subframe#1 or Subframe#6 according to the TDD uplink-downlink
configuration as shown in Table 1.
[0046] For example, in the case of TDD uplink-downlink configuration#6, Subframe#0, Subframe#5,
and Subframe#9 can transmit downlink data and control information, and Subframe#2,
Subframe#3, Subframe#4, Subframe#7, and Subframe#8 can transmit uplink data and control
information. Also, Subframe#1 and Subframe#6 corresponding to special subframes may
transmit downlink control information, and downlink data in some cases, and may transmit
a SRS or a random-access preamble to an uplink.
[0047] The TDD uplink-downlink configuration as described above may be applied to each CC,
that is, to each cell. However, if CCs (that is, CA cells) to which CA is applied
use different duplex schemes, a UE may perform uplink transmission at different locations
of subframes according to the cells.
[0048] FIG. 4 is a view for describing an example of timing for an uplink report when cells
to which CA is applied use different duplex schemes.
[0049] Referring to FIG. 4, Pcell 401 and Scell 402 may be configured for CA of a UE, wherein
the Pcell 401 operates in a TDD mode, and the Scell 402 operates in an FDD mode. The
Pcell 401 may be configured with a frequency f1 403 operating in the TDD mode, and
the Scell 402 may be configured with an uplink frequency f2 405 and a downlink frequency
f3 404 to operate in the FDD mode. The Pcell 401 may operate according to TDD uplink-downlink
configuration#4 among the TDD uplink-downlink configurations shown in Table 1.
[0050] If CA is applied to the LTE-A system, a report period of "periodic CSI reporting"
can be independently set for each cell.
[0051] In the LTE and LTE-A system, a CSI transmission period N
pd for "periodic CSI reporting" of an FDD cell may be set to one of {2, 5, 10, 20, 40,
80, 160, 32, 64, 128}, and a CSI transmission period N
pd for "periodic CSI reporting" of a TDD cell may be set to one of {1, 5, 10, 20, 40,
80, 160}. A unit of a CSI transmission period may be a subframe. A NB may inform a
UE of a CSI transmission period N
pd and a subframe offset N
OFFSET,CQI representing locations of subframes allowing "periodic CSI reporting" in a radio
frame, for "periodic CSI reporting".
[0052] In the example of FIG 4, CSI transmission period N
pd = 5, and subframe offset N
OFFSET,CQI = 0. "Periodic CSI reporting" of a UE can be performed by a subframe satisfying Equation
1 below.
![](https://data.epo.org/publication-server/image?imagePath=2020/49/DOC/EPNWB1/EP15743290NWB1/imgb0001)
where n
f represents a radio frame number, and n
s represents a slot number in the radio frame. Since a subframe is configured with
2 slots, a radio frame may be configured with 20 slots. In the example of FIG. 4,
if n
f=1, a first subframe (n
s = 0 or 1) 408 of the uplink frequency 405 of the Scell 402 may satisfy Equation 1,
as follows.
![](https://data.epo.org/publication-server/image?imagePath=2020/49/DOC/EPNWB1/EP15743290NWB1/imgb0002)
[0053] Accordingly, the first subframe 408 may be a subframe allowing "periodic CSI reporting".
Likewise, since the fifth subframe (n
s = 10 or 11) 409 also satisfies Equation 1 ((10 × 1 + 5 - 0) mod 5 = 0), the fifth
subframe 409 may also be a subframe allowing "periodic CSI reporting".
[0054] As described above, UCI can be transmitted only through the Pcell 401. However, since
the subframes 410 and 413 of the Pcell 401 corresponding to the first and fifth subframes
408 and 409 of the Scell 402 are downlink subframes, the UE cannot perform "periodic
CSI reporting" to the NB through the Pcell 401 in the subframes 410 and 413. That
is, in the example of FIG. 4, the UE cannot perform "periodic CSI reporting" for the
Scell 402, at CSI transmission period N
pd = 5 and subframe offset N
OFFSET,CQI = 0.
[0055] In the example of FIG. 4, the UE can perform "periodic CSI reporting" only in the
uplink subframes 411, 412, 414, and 415 of the Pcell 401.
[0056] Hereinafter, in a CA system in which a cell using the FDD scheme and a cell using
the TDD scheme are aggregated and operated, as described above, embodiments in which
a UE performs "periodic CSI reporting" to a NB will be described.
<First Embodiment>
[0057] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Pcell
(hereinafter, the TDD cell is referred to as a TDD Pcell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Scell (hereinafter,
the FDD cell is referred to as an FDD Scell), operation for performing "periodic CSI
reporting" for the FDD Scell through the TDD Pcell will be described in detail.
[0058] In the first embodiment, a CSI transmission period N
pd that can be set for the FDD Scell may be limited according to TDD uplink-downlink
configurations of the TDD Pcell. That is, according to TDD uplink-downlink configurations
of the TDD Pcell, a CSI transmission period that can be applied to the FDD Scell may
be selected from {2, 5, 10, 20, 40, 80, 160, 32, 64, 128} that are CSI transmission
periods N
pd that can be set for an FDD cell in the LTE and LTE-A system.
[0059] FIGS. 5A and 5B show an example of operation when a CSI transmission period is 2
subframes, according to an embodiment of the present disclosure. FIGS. 5A and 5B show
whether an FDD Scell can support N
pd = 2 according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI transmission
period of the FDD Scell is 2 subframes (N
pd = 2) and a subframe offset of the FDD Scell is an even number (N
OFFSET,CQI = 0, 2, 4, ... ).
[0060] Referring to FIGS. 5A and 5B, in TDD uplink-downlink configuration#0, if N
pd = 2 and N
OFFSET,CQI = even number are applied to Equation 1, subframes satisfying Equation 1 may be Subframe#0
500, Subframe#2 501, Subframe#4 502, Subframe#6 503, and Subframe#8 504 of radio frame#k
570, and Subframe#0 505, Subframe#2 506, Subframe#4 507, Subframe#6 508, and
[0061] Subframe#8 509 of radio frame#k+1 571. Since uplink signal transmission of a UE is
allowed only through UL subframes, the UE can perform periodic CSI reporting through
the Subframe#2 501, Subframe#4 502, and Subframe#8 504 of the radio frame#k 570, and
the Subframe#2 506, Subframe#4 507, and Subframe#8 509 of the radio frame#k+1 571,
which are UL subframes satisfying Equation 1. The interval d between adjacent subframes
allowing periodic CSI reporting of the UE among the UL subframes satisfying Equation
1 may be 2 subframes between the Subframe#2 501 and the Subframe#4 502, 4 subframes
between the Subframe#4 502 and the Subframe#8 504, ..., which satisfy N
pd=2 at least one time. The TDD Pcell which operates according to the TDD uplink-downlink
configuration#0 can partially support the CSI transmission period of the FDD Scell.
[0062] As such, the TDD Scell that operates according to the TDD uplink-downlink configuration#0
may be defined to support "periodic CSI reporting" in which the CSI transmission period
of the FDD Scell is 2 subframes (N
pd = 2) and the subframe offset of the FDD Scell is an even number (N
OFFSET,CQI = even number). A condition for determining whether periodic CSI reporting is allowed
can be generalized to Equation 2, below.
![](https://data.epo.org/publication-server/image?imagePath=2020/49/DOC/EPNWB1/EP15743290NWB1/imgb0003)
where dij represents the interval between subframe#i and subframe#j allowing periodic
CSI reporting with respect to a specific TDD uplink-downlink configuration, wherein
the subframe#i is adjacent to the subframe#j, and min(x) represents a minimum value
of x.
[0063] Referring again to FIGS. 5A and 5B, if the TDD Pcell operates according to TDD uplink-downlink
configuration#0, the UE may perform "periodic CSI reporting" in the order of Subframe#2
501 of radio frame#k 570 → Subframe#4 502 of radio frame#k 570 → Subframe#8 504 of
radio frame#k 570 → Subframe#2 506 of radio frame#k+1 571 → Subframe#4 507 of radio
frame#k+1 571 → Subframe#8 509 of radio frame#k+1 571.
[0064] Then, in the TDD uplink-downlink configuration#1, if N
pd =2 and N
OFFSET,CQI = even number are applied to Equation 1, UL subframes satisfying Equation 1 and allowing
"periodic CSI reporting" of the UE may be the Subframe#2 511 and Subframe#8 514 of
the radio frame#k 570, and the Subframe#2 516 and Subframe#8 519 of the radio frame#k+1
571. The interval d of the subframes may be 6 subframes between the Subframe#2 511
and the Subframe#8 514, 4 subframes between the Subframe#8 514 and the Subframe#2
516, ..., which do not satisfy Equation 2. Accordingly, the TDD uplink-downlink configuration#1
may fail to ensure N
pd = 2 that is to be applied to the FDD Scell.
[0065] As such, the TDD Pcell which operates according to the TDD uplink-downlink configuration#1
may be set to not support "periodic CSI reporting" in which the CSI transmission period
of the FDD Scell is 2 subframes (N
pd = 2) and the subframe offset is an even number (N
OFFSET,CQI = even number).
[0066] Likewise, by applying the operation to the TDD uplink-downlink configurations#2,
#3, #4, #5, and #6, UL subframes satisfying Equation 1 and Equation 2 may be decided
according to the TDD uplink-downlink configurations#2, #3, #4, #5, and #6, as follows.
- TDD uplink-downlink configuration#2
UL subframes satisfying Equation 1: Subframe#2 521 of radio frame#k 570 and Subframe#2
526 of radio frame#k+1 571
- UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#3
- UL subframes satisfying Equation 1: Subframe#2 531 and Subframe#4 532 of radio frame#k
570 and Subframe#2 536 and Subframe#4 537 of radio frame#k+1 571
UL subframes satisfying Equation 2: Subframe#2 531 and Subframe#4 532 of radio frame#k
570 and Subframe#2 536 and Subframe#4 537 of radio frame#k+1 571
[0067] Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
531 of radio frame#k 870 → Subframe#4 532 of radio frame#k 870 → Subframe#2 536 of
radio frame#k+1 571 → Subframe#4 537 of radio frame#k+1 571, in the TDD Pcell according
to the TDD uplink-downlink configuration#3.
- TDD uplink-downlink configuration#4
UL subframes satisfying Equation 1: Subframe#2 541 of radio frame#k 570 and Subframe#2
546 of radio frame#k+1 571
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#5
UL subframes satisfying Equation 1: Subframe#2 551 of radio frame#k 570 and Subframe#2
556 of radio frame#k+1 571
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#6
UL subframes satisfying Equation 1: Subframe#2 561, Subframe#4 562, and Subframe#8
564 of radio frame#k 570, and Subframe#2 566, Subframe#4 567, and Subframe#8 569 of
radio frame#k+1 571
UL subframes satisfying Equation 2: Subframe#2 561, Subframe#4 562, and Subframe#8
564 of radio frame#k 570, and Subframe#2 566, Subframe#4 567, and Subframe#8 569 of
radio frame#k+1 571
[0068] Accordingly, in the TDD Pcell operating according to the TDD uplink-downlink configuration#6,
the UE may perform "periodic CSI reporting" in the order of Subframe#2 561 of radio
frame#k 570 → Subframe#4 562 of radio frame#k 770 → Subframe#8 564 of the radio frame#k
570 → Subframe#2 566 of radio frame#k+1 571 → Subframe#4 567 of radio frame#k+1 571
→ Subframe#8 569 of radio frame#k+1 571.
[0069] Accordingly, the CSI transmission period (N
pd = 2) of the FDD Scell may be applied to the TDD uplink-downlink configurations #0,
#3, and #6 of the TDD Pcell, when N
OFFSET,CQI = even number.
[0070] FIGS. 6A and 6B show another example of operation when a CSI transmission period
is 2 subframes, according to an embodiment of the present disclosure. FIGS. 6A and
6B show whether an FDD Scell can support N
pd according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI transmission
period of the FDD Scell is 2 subframes (N
pd = 2) and a subframe offset N
OFFSET,CQI of the FDD Scell is an odd number.
[0071] Accordingly, the CSI transmission period (N
pd =2) of the FDD Scell may be applied to the TDD uplink-downlink configuration#0 of
the TDD Pcell, when N
OFFSET,CQI = odd number.
[0072] In this case, a UE may perform "periodic CSI reporting" in the order of Subframe#3
601 of radio frame#k 670 → Subframe#7 603 of radio frame#k 670 → Subframe#9 604 of
radio frame#k 670 → Subframe#3 606 of radio frame#k+1 671 → Subframe#7 608 of radio
frame#k+1 671 → Subframe#9 609 of radio frame#k+1 671.
[0073] As a result, the CSI transmission period (N
pd = 2) of the FDD Scell may support the TDD uplink-downlink configurations#0, #3, and
#6, in consideration of all the cases in which N
OFFSET,CQI is an even number or an odd number.
[0074] FIG. 7 shows an example of operation when a CSI transmission period is 5 subframes,
according to an embodiment of the present disclosure. FIG. 7 shows whether an FDD
Scell can support N
pd = 5 according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI transmission
period of the FDD Scell is 5 subframes (N
pd = 5) and a subframe offset N
OFFSET,CQI of the FDD Scell is an arbitrary value.
[0075] Referring to FIG. 7, UL subframes satisfying Equation 1 and Equation 2 may be decided
according to the TDD uplink-downlink configurations, as follows.
- TDD uplink-downlink configuration#0
UL subframes satisfying Equation 1: Subframe#2 702, Subframe#3 703, Subframe#4 704,
Subframe#7 707, Subframe#8 708, and Subframe#9 709 of radio frame#k 770
UL subframes satisfying Equation 2: Subframe#2 702, Subframe#3 703, Subframe#4 704,
Subframe#7 707, Subframe#8 708, and Subframe#9 709 of radio frame#k 770
Accordingly, a UE may perform "periodic CSI reporting" in the order of Subframe#2
702 of radio frame#k 770 → Subframe#7 707 of radio frame#k 770, in the order of Subframe#3
703 of radio frame#k 770 → Subframe#8 708 of radio frame#k 770, or in the order of
Subframe#4 704 of radio frame#k 770 → Subframe#9 709 of radio frame#k 770.
- TDD uplink-downlink configuration#1
UL subframes satisfying Equation 1: Subframe#2 712, Subframe#3 713, Subframe#7 717,
and Subframe#8 718 of radio frame#k 770
UL subframes satisfying Equation 2: Subframe#2 712, Subframe#3 713, Subframe#7 717,
and Subframe#8 718 of radio frame#k 770
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
712 of radio frame#k 770 → Subframe#7 717 of radio frame#k 770, or in the order of
Subframe#3 713 of radio frame#k 770 → Subframe#8 718 of radio frame#k 770.
- TDD uplink-downlink configuration#2
UL subframes satisfying Equation 1: Subframe#2 722 and Subframe#7 727 of radio frame#k
770
UL subframes satisfying Equation 2: Subframe#2 722 and Subframe#7 727 of radio frame#k
770
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
722 of radio frame#k 770 → Subframe#7 727 of radio frame#k 770
- TDD uplink-downlink configuration#3
UL subframes satisfying Equation 1: Subframe#2 732, Subframe#3 733, and Subframe#4
734 of radio frame#k 770
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#4
UL subframes satisfying Equation 1: Subframe#2 742 and Subframe#3 743 of radio frame#k
770
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#5
UL subframes satisfying Equation 1: Subframe#2 752 of radio frame#k 770
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#6
UL subframes satisfying Equation 1: Subframe#2 762, Subframe#3 763, Subframe#4 764,
Subframe#7 767, and Subframe#8 768 of radio frame#k 770
UL subframes satisfying Equation 2: Subframe#2 762, Subframe#3 763, Subframe#7 767,
and Subframe#8 768 of radio frame#k 770
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
762 of radio frame# 770 → Subframe#7 767 of radio frame#k 770, or in the order of
Subframe#3 763 of radio frame#k 770 → Subframe#8 768 of radio frame#k 770.
[0076] As a result, the CSI transmission period (N
pd =5) of the FDD Scell may be applied to the TDD uplink-downlink configurations#0,
#1, #2, and #6 of the TDD Pcell.
[0077] FIGS. 8A and 8B show an example of operation when a CSI transmission period is 32
subframes, according to an embodiment of the present disclosure. FIGS. 8A and 8B show
whether an FDD Scell can support N
pd = 32 according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI transmission
period of the FDD Scell is 32 subframes (N
pd = 32) and a subframe offset N
OFFSET,CQI of the FDD Scell is an arbitrary value.
[0078] Referring to FIGS. 8A and 8B, UL subframes satisfying Equation 1 and Equation 2 may
be decided according to the TDD uplink-downlink configurations, as follows.
- TDD uplink-downlink configuration#0
UL subframes satisfying Equation 1: Subframe#2 800, Subframe#3 801, Subframe#4 802,
Subframe#7 803, Subframe#8 804, and Subframe#9 805 of radio frame#k 880, and Subframe#4
808 and Subframe#9 811 of radio frame#k+3 881
UL subframes satisfying Equation 2: Subframe#2 800 and Subframe#7 803 of radio frame#k
880, and Subframe#4 808 and Subframe#9 811 of radio frame#k+3 881
Accordingly, a UE may perform "periodic CSI reporting" in the order of Subframe#2
800 of radio frame#k 880 → Subframe#4 808 of radio frame#k+3 881, or in the order
of Subframe#7 803 of radio frame#k 880 → Subframe#9 811 of radio frame#k+3 881.
- TDD uplink-downlink configuration#1
UL subframes satisfying Equation 1: Subframe#2 820, Subframe#3 821, Subframe#7 822,
and Subframe#8 823 of radio frame#k 880
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#2
UL subframes satisfying Equation 1: Subframe#2 830 and Subframe#7 831 of radio frame#k
880
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#3
UL subframes satisfying Equation 1: Subframe#2 840, Subframe#3 841, and Subframe#4
842 of radio frame#k 880, and Subframe#4 845 of radio frame#k+3 881
UL subframes satisfying Equation 2: Subframe#2 840 of the radio frame#k 880 and Subframe#4
845 of radio frame#k+3 881
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
840 of radio frame#k 880 →Subframe #4 845 of radio frame#k+3 881
- TDD uplink-downlink configuration#4
UL subframes satisfying Equation 1: Subframe#2 850 and Subframe#3 851 of radio frame#k
880
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#5
UL subframes satisfying Equation 1: Subframe#2 860 of radio frame#k 880
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#6
UL subframes satisfying Equation 1: Subframe#2 870, Subframe#3 871, Subframe#4 872,
Subframe#7 873, and Subframe#8 874 of radio frame#k 880, and Subframe#4 877 of radio
frame#k+3 881
UL subframes satisfying Equation 2: Subframe#2 870 of radio frame#k 880 and Subframe#4
877 of radio frame#k+3 881
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#2
870 of radio frame#k 880 → Subframe#4 877 of radio frame#k+3 881.
[0079] As a result, the CSI transmission period (N
pd = 32) of the FDD Scell may be applied to the TDD uplink-downlink configurations#0,
#3, and #6 of the TDD Pcell.
[0080] FIGS. 9A and 9B show an example of operation when a CSI transmission period is 64
subframes, according to an embodiment of the present disclosure. FIGS. 9A and 9B show
whether an FDD Scell can support N
pd = 64 according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI transmission
period of the FDD Scell is 64 subframes (N
pd = 64) and a subframe offset N
OFFSET,CQI of the FDD Scell is an arbitrary value.
[0081] Referring to FIGS. 9A and 9B, UL subframes satisfying Equation 1 and Equation 2 may
be decided according to the TDD uplink-downlink configurations, as follows.
- TDD uplink-downlink configuration#0
UL subframes satisfying Equation 1: Subframe#2 900, Subframe#3 901, Subframe#4 902,
Subframe#7 903, Subframe#8 904, and Subframe#9 905 of radio frame#k 981, Subframe#7
909 and Subframe#8 910 of radio frame#k+6 982, and Subframe#2 912 and Subframe#3 913
of radio frame#k+7 983
UL subframes satisfying Equation 2: Subframe#3 901, Subframe#4 902, Subframe#8 904,
and Subframe#9 905 of radio frame#k 981, Subframe#7 909 and Subframe#8 910 of radio
frame#k+6 982, and Subframe#2 912 and Subframe#3 913 of radio frame#k+7 983
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#3
901 of radio frame#k 981 → Subframe#7 909 of radio frame#k+6 982, in the order of
Subframe#4 902 of radio frame#k 981 → Subframe#8 910 of radio frame#k+6 982, in the
order of Subframe#8 904 of radio frame#k 981 → Subframe#2 912 of radio frame#k+7 983,
or in the order of Subframe#9 905 of radio frame#k 981 → Subframe#3 913 of radio frame#k+7
983.
- TDD uplink-downlink configuration#1
UL subframes satisfying Equation 1: Subframe#2 920, Subframe#3 921, Subframe#7 922,
and Subframe#8 923 of radio frame#k 981, Subframe#7 926 and Subframe#8 927 of radio
frame#k+6 982, and Subframe#2 928 and Subframe#3 929 of radio frame#k+7 983
UL subframes satisfying Equation 2: Subframe#3 921 and Subframe#8 923 of radio frame#k
981, Subframe#7 926 of radio frame#k+6 982, and Subframe#2 928 of radio frame#k+7
983
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#3
921 of radio frame#k 981 → Subframe#7 926 of radio frame#k+6 982, or in the order
of Subframe#8 923 of radio frame#k 981 → Subframe#2 928 of radio frame#k+7 983.
- TDD uplink-downlink configuration#2
UL subframes satisfying Equation 1: Subframe#2 930 and Subframe#7 931 of radio frame#k
981
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#3
UL subframes satisfying Equation 1: Subframe#2 940, Subframe#3 941, and Subframe#4
942 of radio frame#k 981
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#4
UL subframes satisfying Equation 1: Subframe#2 950 and Subframe#3 951 of radio frame#k
981
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#5
UL subframes satisfying Equation 1: Subframe#2 960 of radio frame#k 981
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#6
UL subframes satisfying Equation 1: Subframe#2 970, Subframe#3 971, Subframe#4 972,
Subframe#7 973, and Subframe#8 974 of radio frame#k 981, Subframe#7 978 and Subframe#8
979 of radio frame#k+6 982, and Subframe#2 980 of radio frame#k+7 983
UL subframes satisfying Equation 2: Subframe#3 971, Subframe#4 972, and Subframe#8
974 of radio frame#k 981, Subframe#7 978 and Subframe#8 979 of radio frame#k+6 982,
and Subframe#2 980 of radio frame#k+7 983
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#3
971 of radio frame#k 981 → Subframe#7 978 of radio frame#k+6 982, in the order of
Subframe#4 972 of radio frame#k 981 → Subframe#8 979 of radio frame#k+6 982, or in
the order of Subframe#8 974 of radio frame#k 981 → Subframe#2 980 of radio frame#k+7
983.
[0082] As a result, the CSI transmission period (N
pd = 64) of the FDD Scell may be applied to the TDD uplink-downlink configurations #0,
#1, and #6 of the TDD Pcell.
[0083] FIGS. 10A and 10B shows an example of operation when a CSI transmission period is
128 subframes, according to an embodiment of the present disclosure. FIGS. 9A and
9B show whether an FDD Scell can support N
pd = 128 according to TDD uplink-downlink configurations of a TDD Pcell, when a CSI
transmission period of the FDD Scell is 128 subframes (N
pd = 128) and a subframe offset N
OFFSET,CQI of the FDD Scell is an arbitrary value.
[0084] Referring to FIGS. 10A and 10B, UL subframes satisfying Equation 1 and Equation 2
may be decided according to the TDD uplink-downlink configurations, as follows.
- TDD uplink-downlink configuration#0
UL subframes satisfying Equation 1: Subframe#2 1000, Subframe#3 1001, Subframe#4 1002,
Subframe#7 1003, Subframe#8 1004, and Subframe#9 1005 of radio frame#k 1080, and Subframe#2
1006 and Subframe#7 1009 of radio frame#k+13 1081
UL subframes satisfying Equation 2: Subfame#4 1002 and Subframe#9 1005 of radio frame#k
1080, and Subframe#2 1006 and Subframe#7 1009 of radio frame#k+13 1081
Accordingly, a UE may perform "periodic CSI reporting" in the order of Subframe#4
1002 of radio frame#k 1080 → Subframe#2 1006 of radio frame#k+13 1081, or in the order
of Subframe#9 1005 of radio frame#k 1080 → Subframe#7 1009 of radio frame#k+13 1081.
- TDD uplink-downlink configuration#1
UL subframes satisfying Equation 1: Subfame#2 1020, Subframe#3 1021, Subframe#7 1022,
and Subframe#8 1023 of radio frame#k 1080
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#2
UL subframes satisfying Equation 1: Subframe#2 1030 and Subframe#7 1031 of radio frame#k
1080
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#3
UL subframes satisfying Equation 1: Subframe#2 1040, Subframe#3 1041, and Subframe#4
1042 of radio frame#k 1080, and Subframe#2 1043 of radio frame #k+13 1081
UL subframes satisfying Equation 2: Subframe#4 1042 of radio frame#k 1080, and Subframe#2
1043 of radio frame#k+13 1081
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#4
1042 of radio frame#k 1080 → Subframe#2 1043 of radio frame#k+13 1081.
- TDD uplink-downlink configuration#4
UL subframes satisfying Equation 1: Subframe#2 1050 and Subframe#3 1051 of radio frame#k
1080
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#5
UL subframes satisfying Equation 1: Subframe#2 1060 of radio frame#k 1080
UL subframes satisfying Equation 2: None
- TDD uplink-downlink configuration#6
UL subframes satisfying Equation 1: Subframe#2 1070, Subframe#3 1071, Subframe#4 1072,
Subframe#7 1073, and Subframe#8 1074 of radio frame#k 1080, and Subframe#2 1075 of
radio frame#k+13 1031
UL subframes satisfying Equation 2: Subframe#7 1072 of radio frame#k 1080, and Subframe#2
1075 of radio frame#k+13 1031
Accordingly, the UE may perform "periodic CSI reporting" in the order of Subframe#4
1072 of radio frame#k 1080 → Subframe#2 1075 of radio frame#k+13 1081.
[0085] As a result, the CSI transmission period (N
pd = 128) of the FDD Scell may be applied to the TDD uplink-downlink configurations#0,
#3, and #6 of the TDD Pcell.
[0086] Since all the TDD uplink-downlink configurations satisfy periodicity of 10ms, the
CSI transmission periods N
pd {10, 20, 40, 80, 160} of the FDD Scell, corresponding to multiples of 10, may be
applied to all the TDD uplink-downlink configurations.
[0087] In summary, in the first embodiment, TDD uplink-downlink configurations that can
be applied for each CSI transmission period N
pd of the FDD Scell may be decided as shown in Table 2.
[Table 2]
Npd (FDD Scell) |
TDD Uplink-downlink configuration (TDD Pcell) |
2 |
{0, 3, 6} |
5 |
{0, 1, 2, 6} |
32 |
{0, 3, 6} |
64 |
{0, 1, 6} |
128 |
{0, 3, 6} |
{10, 20, 40, 80, 160} |
{0, 1, 2, 3, 4, 5, 6} |
[0088] In other words, if the TDD Pcell has the TDD uplink-downlink configuration#0, the
N
pd of the FDD Scell may be selected from {2, 5, 32, 64, 128} and {10, 20, 40, 80, 160},
if the TDD Pcell has the TDD uplink-downlink configuration#1, the N
pd of the FDD Scell may be selected from {5, 64} and {10, 20, 40, 80, 160}, if the TDD
Pcell has the TDD uplink-downlink configuration#2, the N
pd of the FDD Scell may be selected from {5} and {10, 20, 40, 80, 160}, if the TDD Pcell
has the TDD uplink-downlink configuration#3, the N
pd of the FDD Scell may be selected from {2, 32, 128} and {10, 20, 40, 80, 160}, if
the TDD Pcell has the TDD uplink-downlink configurations#4 and #5, the N
pd of the FDD Scell may be selected from {10, 20, 40, 80, 160}, if the TDD Pcell has
the TDD uplink-downlink configuration#6, the N
pd of the FDD Scell may be selected from {2, 5, 32, 64, 128} and {10, 20, 40, 80, 160}.
[0089] FIG. 11 is a flowchart illustrating a method of setting a CSI transmission period
N
pd, according to an embodiment of the present disclosure.
[0090] Referring to FIG. 11, in operation 1100, a NB may identify a TDD uplink-downlink
configuration defined for a TDD Pcell of a UE. The TDD uplink-downlink configuration
may have been decided, when the TDD Pcell for the UE was configured, in consideration
of an uplink-downlink traffic state of the TDD Pcell, TDD uplink-downlink configurations
of neighboring cells, etc.
[0091] Then, in operation 1102, the NB may decide a CSI transmission period N
pd that is to be set for an FDD Scell. More specifically, the NB may select one from
{2, 5, 10, 20, 40, 80, 160, 32, 64, 128} that can be set for an FDD Scell.
[0092] Then, in operation 1104, the NB may determine whether UL subframes of the TDD Pcell
satisfying Equation 1 with respect to the CSI transmission period N
pd satisfy Equation 2. If the NB determines that the UL subframes of the TDD Pcell satisfy
Equation 2, the NB may decide the CSI transmission period N
pd as a CSI transmission period N
pd of the FDD Scell, in operation 1106, include information about the decided CSI transmission
period N
pd in a predetermined signaling message, and then transmit the predetermined signaling
message to the UE, in operation 1110. Meanwhile, if the NB determines that the UL
subframes of the TDD Pcell do not satisfy Equation 2, the NB may return to operation
1102 to again set a CSI transmission period N
pd, in operation 1108.
[0093] According to another embodiment, if a Pcell configured for a UE is a TDD mode, and
a Scell is an FDD mode, the NB may identify a TDD uplink-downlink configuration of
the TDD Pcell, and acquire a set of CSI transmission periods of the FDD Scell that
can be used for the TDD uplink-downlink configuration. For example, the NB may include
a memory that stores groups of CSI transmission periods for TDD uplink-downlink configurations
of a TDD Pcell, based on Table 2. Then, the CSI transmission period of the FDD Scell
may be selected from the acquired set of CSI transmission periods according to a predetermined
condition.
<Second Embodiment>
[0094] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Pcell
(hereinafter, the TDD cell is referred to as a TDD Pcell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Scell (hereinafter,
the FDD cell is referred to as an FDD Scell), operation for performing "periodic CSI
reporting" for the FDD Scell through the TDD Pcell will be described in detail, below.
[0095] In the second embodiment, although a CSI transmission period N
pd that can be set for the FDD Scell is not limited according to TDD uplink-downlink
configurations of the TDD Pcell, the CSI transmission period for the FDD Scell may
be selected from {2, 5, 10, 20, 40, 80, 160, 32, 64, 128} that are CSI transmission
periods N
pd that can be set for an FDD cell, like in the typical LTE and LTE-A system. A UE may
perform "periodic CSI reporting" in UL subframes of the TDD Pcell satisfying Equation
1. Accordingly, in some cases, the UE may report CSI at time intervals that are longer
than a CSI transmission period set by the NB.
[0096] For example, referring to FIGS. 5A and 5B, if N
pd = 2 and N
OFFSET,CQI = even number with respect to an FDD Scell, and a TDD Pcell is configured to0 the
TDD uplink-downlink configuration#4, UL subframes satisfying Equation 1 and allowing
"periodic CSI reporting" may be Subframe#2 541 of radio frame#k 570 and Subframe#2
546 of radio frame#k+1 571. Accordingly, the UE may perform "periodic CSI reporting"
in the order of Subframe#2 541 of radio frame#k 570 → Subframe#2 546 of radio frame#k+1
571. A time interval between the Subframe#2 541 of the radio frame#k 570 and the Subframe#2
546 of the radio frame#k+1 571 may be 10 subframes which is longer than the CSI transmission
period (N
pd = 2) set to be applied to the FDD Scell. That is, although a CSI transmission period
N
pd that can be set by a NB with respect to an FDD Scell is not limited, a CSI transmission
period in which a UE actually performs "periodic CSI reporting" may be lengthened.
<Third Embodiment>
[0097] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Pcell
(hereinafter, the TDD cell is referred to as a TDD Pcell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Scell (hereinafter,
the FDD cell is referred to as an FDD Scell), operation for performing "periodic CSI
reporting" for the FDD Scell through the TDD Pcell will be described in detail, below.
[0098] According to the third embodiment, in the CA, a CSI transmission period N
pd that can be applied to an FDD Scell may be set based on a separate group decided
in consideration of possible CSI transmission periods of a TDD cell, instead of {2,
5, 10, 20, 40, 80, 160, 32, 64, 128} decided for an FDD cell of a single carrier wave.
[0099] Method 1: CSI transmission periods N
pd that can be applied to an FDD Scell may be selected from among CSI transmission periods
N
pd that can be applied to a TDD Pcell. That is, a group of CSI transmission periods
N
pd that can be applied to an FDD Scell may be {1, 5, 10, 20, 40, 80, 160}. A NB may
select an element from the group to decide N
pd for an FDD Scell configured for a UE, and transmit information about the selected
N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the TDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB. Herein, N
pd=1 means that CSI reporting is performed in all UL subframes of the TDD Pcell.
[0100] Method 2: CSI transmission periods N
pd that can be applied to an FDD Scell may be selected from a group {5, 10, 20, 40,
80, 160} that can be applied in common to TDD cells and FDD cells. A NB may select
an element from the group to decide N
pd for an FDD Scell configured for a UE, and transmit information about the selected
N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the TDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB.
[0101] According to the third embodiment, the NB and UE may set a CSI transmission period
N
pd that is applied to the FDD Scell or the FDD cell, according to whether CA has been
configured between the FDD cell and the TDD cell.
[0102] FIG. 12 is a flowchart illustrating a method of setting a CSI transmission period,
according to another embodiment of the present disclosure. The flowchart shown in
FIG. 12 can be applied to both a NB and a UE.
[0103] First, operation of a NB will be described with reference to FIG. 12, below. In operation
1200, the NB may determine whether CA has been configured between a TDD cell and an
FDD cell with respect to a UE. If the NB determines that CA has been configured between
the TDD cell and the FDD cell, the NB may set a CSI transmission period N
pd that is applied to an FDD Scell, based on {1, 5, 10, 20, 40, 80, 160} according to
Method 1 and {5, 10, 20, 40, 80, 160} according to Method 2, in operation 1202.
[0104] Meanwhile, if the NB determines that no CA has been configured between the TDD cell
and the FDD cell, that is, if the FDD cell has been configured alone with respect
to the UE, or if CA has been configured between FDD cells, the NB may set a CSI transmission
period N
pd that is applied to the FDD Scell, based on a group of CSI transmission periods N
pd defined for FDD cells of the typical LTE and LTE-A system, in operation 1204.
[0105] Then, in operation 1206, the NB may transmit information about the N
pd to the UE. Then, the UE may periodically report CSI for the FDD Scell in UL subframes
of the TDD Pcell satisfying Equation 1, based on the received information about the
N
pd.
[0106] According to another embodiment, if the UE is configured to select N
pd through the same algorithm as that used in the NB, the NB may omit operation 1206
of transmitting information about N
pd, and the UE may itself decide N
pd without receiving information about N
pd from the NB, and periodically report CSI for the FDD Scell using the decided N
pd.
[0107] Now, operation of the UE will be described with reference to FIG. 12. In operation
1200, the UE may determine whether CA between the TDD cell and the FDD cell has been
configured by the NB. If the UE determines that CA between the TDD cell and the FDD
cell has been configured, the UE may set a CSI transmission period N
pd that is applied to the FDD Scell, based on {1, 5, 10, 20, 40, 80, 160} according
to Method 1 or {5, 10, 20, 40, 80, 160} according to Method 2, in operation 1202.
[0108] In contrast, if the UE determines that no CA between the TDD cell and the FDD cell
has been configured, that is, if the FDD cell has been configured alone with respect
to the UE, or if CA has been configured between FDD cells, the UE may set a CSI transmission
period N
pd that is applied to the FDD Scell, based on a group of CSI transmission periods N
pd defined for FDD cells of the typical LTE and LTE-A system, in operation 1204.
[0109] Then, in operation 1206, the UE may perform "periodic CSI reporting" for the FDD
Scell, based on the set N
pd. According to another embodiment, the UE may receive information about N
pd from the NB, instead of itself setting N
pd, and perform "periodic CSI reporting" for the FDD Scell based on the received N
pd.
<Fourth Embodiment>
[0110] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Scell
(hereinafter, the TDD cell is referred to as a TDD Scell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Pcell (hereinafter,
the FDD cell is referred to as an FDD Pcell), operation for performing "periodic CSI
reporting" for the TDD Scell through the FDD Pcell will be described in detail, below.
[0111] A CSI transmission period N
pd for the TDD Scell may be set to one of CSI transmission periods N
pd that can be applied to TDD cells, regardless of whether CA has been configured. That
is, one of {1, 5, 10, 20, 40, 80, 160} that can be set for TDD cells of the typical
LTE and LTE-A system may be selected as N
pd of the TDD Scell, and the NB may transmit information about the selected N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the PDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB. Accordingly, periodic CSI reporting for the TDD Scell may be
performed in each subframe (N
pd =1) through the FDD Pcell.
<Fifth Embodiment>
[0112] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Scell
(hereinafter, the TDD cell is referred to as a TDD Scell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Pcell (hereinafter,
the FDD cell is referred to as an FDD Pcell), operation for performing "periodic CSI
reporting" for the TDD Scell through the FDD Pcell will be described in detail, below.
[0113] If CA has been configured, a CSI transmission period N
pd for the TDD Scell may be set to one of CSI transmission periods N
pd that can be applied to the FDD Pcell. That is, if CA has been configured between
the TDD Scell and the FDD Pcell, one of {2, 5, 10, 20, 40, 80, 160, 32, 64, 128} that
can be set for FDD cells of the typical LTE and LTE-A system may be selected as N
pd of the TDD Scell, and the NB may transmit information about the selected N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the FDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB. Accordingly, in the CA, the UE may perform "periodic CSI reporting"
for the TDD Scell at N
pd = {2, 32, 64, 128} not defined for TDD cells of the typical LTE and LTE-A system,
through the FDD Pcell.
<Sixth Embodiment>
[0114] In a CA system in which a cell (also, referred to as an FDD cell) using the FDD scheme
and a cell (also, referred to as a TDD cell) using the TDD scheme are aggregated and
operated, when the TDD cell is configured with a frequency f1 to operate as a Scell
(hereinafter, the TDD cell is referred to as a TDD Scell), and the FDD cell is configured
with an uplink frequency f2 and a downlink frequency f3 to operate as a Pcell (hereinafter,
the FDD cell is referred to as an FDD Pcell), operation for performing "periodic CSI
reporting" for the TDD Scell through the FDD Pcell will be described in detail, below.
[0115] According to the sixth embodiment, in the CA, a CSI transmission period N
pd that can be applied to a TDD Scell may be set based on a separate group decided in
consideration of possible CSI transmission periods of an FDD cell, instead of {1,
5, 10, 20, 40, 80, 160} decided for a TDD cell of a single carrier wave.
[0116] Method 1: CSI transmission period N
pd that can be applied to a TDD Scell may be selected from among CSI transmission periods
N
pd that can be applied to an FDD Pcell. That is, a group of CSI transmission periods
N
pd that can be applied to a TDD Scell may be {2, 5, 10, 20, 40, 80, 160, 32, 64, 128}.
A NB may select an element from the group to decide N
pd for a TDD Scell configured for a UE, and transmit information about the selected
N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the FDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB. Accordingly, in the CA, the UE may perform "periodic CSI reporting"
for the TDD Scell at N
pd = {2, 32, 64, 128} not defined for TDD cells of the typical LTE and LTE-A system,
through the FDD Pcell.
[0117] Method 2: CSI transmission period N
pd that can be applied to a TDD Scell may be selected from {5, 10, 20, 40, 80, 160}
that can be applied in common to TDD cells and FDD cells. A NB may select an element
from the group to decide N
pd for a TDD Scell configured for a UE, and transmit information about the selected
N
pd to the UE. The UE may perform "periodic CSI reporting" in UL subframes of the FDD
Pcell satisfying Equation 1, based on the N
pd indicated by the NB.
[0118] According to the sixth embodiment, the NB and UE may set a CSI transmission period
N
pd that is applied to the TDD Scell or the TDD cell, according to whether CA has been
configured between the TDD cell and the FDD cell. That is, if CA has been configured
between the TDD cell and the FDD cell, a CSI transmission period N
pd that is applied to the TDD Scell may be set according to Method 1 or Method 2. If
no CA has been configured between the TDD cell and the FDD cell, that is, if the TDD
cell has been operated alone, or if CA has been configured between TDD cells, a CSI
transmission period N
pd that is applied to a TDD cell may be selected from among CSI transmission periods
N
pd defined for TDD cells of the typical LTE and LTE-A system.
[0119] FIG. 13 is a flowchart illustrating a method of setting a CSI transmission period,
according to another embodiment of the present disclosure. The flowchart shown in
FIG. 13 can be applied to both a NB and a UE.
[0120] First, operation of a NB will be described with reference to FIG. 13, below. In operation
1300, the NB may determine whether CA between a TDD cell and an FDD cell has been
configured with respect to a UE. If the NB determines that CA between the TDD cell
and the FDD cell has been configured, the NB may set a CSI transmission period N
pd that is applied to a TDD Scell, based on {2, 5, 10, 20, 40, 80, 160, 32, 64, 128}
according to Method 1 or {5, 10, 20, 40, 80, 160} according to Method 2, in operation
1302.
[0121] In contrast, if the NB determines that no CA has been configured between the TDD
cell and the FDD cell, that is, if the TDD cell has been configured alone with respect
to the UE, or if CA has been configured between TDD cells, the NB may set a CSI transmission
period N
pd that is applied to the TDD cell, based on a group of CSI transmission periods N
pd defined for TDD cells of the typical LTE and LTE-A system, in operation 1304.
[0122] In operation 1306, the NB may transmit information about the N
pd to the UE. Then, the UE may periodically report CSI for the TDD Scell in UL subframes
of the FDD Pcell satisfying Equation 1, based on the received information about the
N
pd.
[0123] According to another embodiment, if the UE is configured to select N
pd through the same algorithm as that used in the NB, the NB may omit operation 1306
of transmitting information about N
pd, and the UE may itself decide N
pd without receiving information about N
pd from the NB, and periodically report CSI for the FDD Scell using the decided N
pd.
[0124] Now, operation of the UE will be described with reference to FIG. 13. In operation
1300, the UE may determine whether CA between the TDD cell and the FDD cell has been
configured by the NB. If the UE determines that CA between the TDD cell and the FDD
cell has been configured, the UE may set a CSI transmission period N
pd that is applied to the TDD Scell, based on {2, 5, 10, 20, 40, 80, 160, 32, 64, 128}
according to Method 1 or {5, 10, 20, 40, 80, 160} according to Method 2, in operation
1302.
[0125] In contrast, if the UE determines that no CA between the TDD cell and the FDD cell
has been configured, that is, if the TDD cell has been configured alone with respect
to the UE, or if CA has been configured between TDD cells, the UE may set a CSI transmission
period N
pd that is applied to the TDD Scell, based on a group of CSI transmission periods N
pd defined for TDD cells of the typical LTE and LTE-A system, in operation 1304.
[0126] In operation 1306, the UE may perform "periodic CSI reporting" for the TDD Scell
based on the set N
pd. According to another embodiment, the UE may receive information about N
pd from the NB, instead of itself setting N
pd, and perform "periodic CSI reporting" for the TDD Scell, based on the received N
pd.
[0127] FIG. 14 is a flowchart illustrating a method in which a UE performs "periodic CSI
reporting", according to an embodiment of the present disclosure.
[0128] Referring to FIG. 14, in operation 1400, the UE may acquire information about a TDD
uplink-downlink configuration and information about a CSI reporting configuration,
from a NB. The information about the CSI reporting configuration may be at least one
of a CSI transmission period N
pd and a subframe offset N
OFFSET,CQI. In operation 1402, the UE may determine a CSI transmission time for "periodic CSI
reporting". At this time, the UE may determine the CSI transmission time according
to one of the above-described embodiments. If it is needed to perform "periodic CSI
reporting" in Subframe#n, the UE may determine whether it is needed to perform PUSCH
transmission in the Subframe#n, in operation 1404. If the UE determines that it is
needed to perform PUSCH transmission in the Subframe#n, the UE may include CSI in
PUSCH in the Subframe#n, and transmit the PUSCH to a NB, in operation 1406. If the
UE determines that it is not needed to perform PUSCH transmission in the Subframe#n
in operation 1404, the UE may transmit CSI through PUCCH in the Subframe#n, in operation
1408.
[0129] FIG. 15 shows a configuration of a UE transmission apparatus according to an embodiment
of the present disclosure. For convenience of description, components not directly
related to the present disclosure will be neither shown nor described.
[0130] Referring to FIG. 15, a UE 1500 may include a TDD cell transmitter 1502, an FDD cell
transmitter 1510, and a controller 1520. The TDD cell transmitter 1502 may include
a PUCCH block 1504, a multiplexer 1506, and a transmit Radio Frequency (RF) block
1508, and the FDD cell transmitter 1510 may include a PUCCH block 1512, a multiplexer
1514, and a transmit RF block 1516. The controller 1520 may control the individual
blocks of the FDD cell transmitter 1510 and the TDD cell transmitter 1502 according
to one of the above-described embodiments with respect to "periodic CSI reporting"
of the UE 1500, with reference to control information received from a NB. The control
information may include at least one of information about a TDD uplink-downlink configuration
and information about a CSI reporting configuration, according to an embodiment.
[0131] The PUCCH block 1504 of the TDD cell transmitter 1502 may generate a PUCCH signal
including CSI, if a TDD Pcell is configured with respect to the UE 1500 by the NB.
If there is another uplink transmission signal that is transmitted to the TDD cell,
the UE 1500 may multiplex the PUCCH signal with the other uplink transmission signal
through the multiplexer 1506, perform signal processing on the multiplexed signal
through the transmit RF block 1508, and then transmit the signal-processed signal
to the NB.
[0132] The PUCCH block 1512 of the FDD cell transmitter 1510 may generate a PUCCH signal
including CSI, if an FDD Pcell for the UE 1500 is configured by the NB. If there is
another uplink transmission signal that is transmitted to the FDD cell, the UE 1500
may multiplex the PUCCH signal with the other uplink transmission signal through the
multiplexer 1514, perform signal processing on the multiplexed signal through the
transmit RF block 1516, and then transmit the signal-processed signal to the NB.
[0133] FIG. 16 shows a configuration of a NB reception apparatus according to an embodiment
of the present disclosure. For convenience of description, components not directly
related to the present disclosure will be neither shown nor described.
[0134] Referring to FIG. 16, a NB 1600 may include a TDD cell receiver 1602, an FDD cell
receiver 1610, and a controller 1620. The TDD cell receiver 1602 may include a PUCCH
block 1604, a demultiplexer 1606, and a receive RF block 1608, and the FDD cell receiver
1610 may include a PUCCH block 1612, a demultiplexer 1614, and a receive RF block
1616. The controller 1620 may control the individual blocks of the TDD cell receiver
1602 and the FDD cell receiver 1610 according to one of the above-described embodiments
so that the NB 1600 can receive CSI transmitted from a UE. According to an embodiment,
the controller 1620 may transmit one of information about a TDD uplink-downlink configuration
and information about a CSI reporting configuration to a UE through a separate transmitter
(not shown).
[0135] If a TDD Pcell for a UE is configured, the TDD cell receiver 1602 may perform signal
processing on a signal received from the UE through the receive RF block 1616, extract
a PUCCH signal from the signal through the demultiplexer 1606, and then acquire CSI
from the PUCCH signal through the PUCCH block 1604.
[0136] If an FDD Pcell for a UE is configured, the FDD cell receiver 1610 may perform signal
processing on a signal received from the UE through the receive RF block 1616, extract
a PUCCH signal from the signal through the demultiplexer 1614, and then acquire CSI
from the PUCCH signal through the PUCCH block 1612.
<Seventh Embodiment>
[0137] The seventh embodiment relates to a method of deciding a subframe offset N
OFFSET,CQI for CSI reporting of a Scell when CA is configured between a TDD cell and an FDD
cell. More specifically, the subframe offset N
OFFSET,CQI for CSI reporting of the Scell may be decided using the method of deciding a CSI
transmission period N
pd for CSI reporting of a Scell, as described above in the first to sixth embodiments.
In a LTE system, a NB may provide a UE with related information for periodic CSI reporting
through cqi-pmi-ConfigIndex (I
CQI/PMI) as a parameter that is transmitted through upper-layer signaling, for example, Radio
Resource Control (RRC) signaling. The related information for periodic CSI reporting
may be a CSI transmission period N
pd and a subframe offset N
OFFSET,CQI. cqi-pmi-ConfigIndex is a parameter that is used to decide how often a UE reports
CQI and PMI of CSI through PUCCH.
[0138] Table 3 and Table 4 show mapping relationships of I
CQI/PMI to N
pd and N
OFFSET,CQI defined for an FDD cell and a TDD cell of a LTE system. For example, in an FDD cell
in which no CA has been configured, if a UE receives a signalling of I
CQI/PMI = 2 from a NB, the UE may decide related information for periodic CSI reporting of
the FDD cell, as N
pd = 5 and N
OFFSET,CQI = 0, according to Table 3. Likewise, the NB may decide related information for periodic
CSI reporting of the FDD cell, according to Table 3, and then expect to receive CSI
from the UE at a decided timing.
[0139] The following Table 3 shows mapping relationships of I
CQI/PMI to N
pd and N
OFFSET,CQI for FDD.
<Table 3>
ICQI/PMI |
Value of Npd |
Value of NOFFSET,CQI |
0 ≤ ICQI/PMI ≤ 1 |
2 |
ICQI/PMI |
2 ≤ ICQI/PMI ≤ 6 |
5 |
ICQI/PMI - 2 |
7 ≤ ICQI/PMI ≤ 16 |
10 |
ICQI/PMI - 7 |
17 ≤ ICQI/PMI ≤ 36 |
20 |
ICQI/PMI - 17 |
37 ≤ ICQI/PMI ≤ 76 |
40 |
ICQI/PMI - 37 |
77 ≤ ICQI/PMI ≤ 156 |
80 |
ICQI/PMI - 77 |
157 ≤ ICQI/PMI ≤ 316 |
160 |
ICQI/PMI - 157 |
ICQI/PMI = 317 |
Reserved |
318 ≤ ICQI/PMI ≤ 349 |
32 |
ICQI/PMI - 318 |
350 ≤ ICQI/PMI ≤ 413 |
64 |
ICQI/PMI - 350 |
414 ≤ ICQI/PMI ≤ 541 |
128 |
ICQI/PMI - 414 |
542 ≤ ICQI/PMI ≤ 1023 |
Reserved |
[0140] The following Table 4 shows mapping relationships of I
CQI/PMI to N
pd and N
OFFSET,CQI for TDD.
<Table 4>
ICQI/PMI |
Value of Npd |
Value of NOFFSET,CQI |
ICQI/PMI = 0 |
1 |
ICQI/PMI |
1 ≤ ICQI/PMI ≤ 5 |
5 |
ICQI/PMI - 1 |
6 ≤ ICQI/PMI ≤ 15 |
10 |
ICQI/PMI - 6 |
16 ≤ ICQI/PMI ≤ 35 |
20 |
ICQI/PMI - 16 |
36 ≤ ICQI/PMI ≤ 75 |
40 |
ICQI/PMI - 36 |
76 ≤ ICQI/PMI ≤ 155 |
80 |
ICQI/PMI - 76 |
156 ≤ ICQI/PMI ≤ 315 |
160 |
ICQI/PMI - 156 |
316 ≤ ICQI/PMI ≤ 1023 |
Reserved |
[0141] In a CA system in which a cell using the FDD scheme and a cell using the TDD scheme
are aggregated to operate a TDD Pcell and an FDD Scell, a method of deciding N
pd and N
OFFSET,CQI to perform "periodic CSI reporting" for the FDD Scell through the TDD Pcell will
be described in regard of the first to third embodiments, based on Table 3 and Table
4.
- First Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the FDD Scell, according to Table 3. However, as
defined in the first embodiment, Npd that can be set for the FDD Scell may be limited according to a TDD uplink-downlink
configuration of the TDD Pcell.
- Second Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the FDD Scell, according to Table 3.
- Method 1 of Third Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the FDD Scell, according to Table 4.
- Method 2 of Third Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the FDD Scell, according to one of Table 5, Table
6, and Table 7. Table which is to be used among Table 5, Table 6, and Table 7 may
be defined in a specification, or may be appointed through signaling between the UE
and NB. Table 5 is Table resulting from removing an item of Npd =1 from Table 4. Table 6 is Table resulting from removing items of Npd = 2, 32, 64, 128 from Table 3. Table 7 is Table reconfigured with Npd = 5, 10, 20, 40, 80, 160 and NOFFSET,CQI corresponding to the Npd values.
<Table 5>
ICQI/PMI |
Value of Npd |
Value of NOFFSET,CQI |
1 ≤ ICQI/PMI ≤ 5 |
5 |
ICQI/PMI - 1 |
6 ≤ ICQI/PMI ≤ 15 |
10 |
ICQI/PMI - 6 |
16 ≤ ICQI/PMI ≤ 35 |
20 |
ICQI/PMI - 16 |
36 ≤ ICQI/PMI ≤ 75 |
40 |
ICQI/PMI - 36 |
76 ≤ ICQI/PMI ≤ 155 |
80 |
ICQI/PMI - 76 |
156 ≤ ICQI/PMI ≤ 315 |
160 |
ICQI/PMI - 156 |
316 ≤ ICQI/PMI ≤ 1023 |
Reserved |
<Table 6>
ICQI/PMI |
Value of Npd |
Value of NOFFSET,CQI |
2 ≤ ICQI/PMI ≤ 6 |
5 |
ICQI/PMI - 2 |
7 ≤ ICQI/PMI ≤ 16 |
10 |
ICQI/PMI - 7 |
17 ≤ ICQI/PMI ≤ 36 |
20 |
ICQI/PMI - 17 |
37 ≤ ICQI/PMI ≤ 76 |
40 |
ICQI/PMI - 37 |
77 ≤ ICQI/PMI ≤ 156 |
80 |
ICQI/PMI - 77 |
157 ≤ ICQI/PMI ≤ 316 |
160 |
ICQI/PMI - 157 |
<Table 7>
ICQI/PMI |
Value of Npd |
Value of NOFFSET,CQI |
0 ≤ ICQI/PMI ≤ 4 |
5 |
ICQI/PMI |
5 ≤ ICQI/PMI ≤ 14 |
10 |
ICQI/PMI - 5 |
15 ≤ ICQI/PMI ≤ 34 |
20 |
ICQI/PMI - 15 |
35 ≤ ICQI/PMI ≤ 74 |
40 |
ICQI/PMI - 35 |
75 ≤ ICQI/PMI ≤ 154 |
80 |
ICQI/PMI - 75 |
155 ≤ ICQI/PMI ≤ 314 |
160 |
ICQI/PMI - 155 |
[0142] Now, in a CA system in which a cell using the FDD scheme and a cell using the TDD
scheme are aggregated to operate a TDD Pcell and an FDD Scell, a method of deciding
N
pd and N
OFFSET,CQI to perform "periodic CSI reporting" for the TDD Scell through the FDD Pcell will
be described in regard of the fourth to sixth embodiments, based on Table 3 and Table
4.
- Fourth Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the TDD scell, according to Table 4.
- Fifth Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the TDD scell, according to Table 3.
- Method 1 of Sixth Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the TDD scell, according to Table 3.
- Method 2 of Seventh Embodiment: UE may decide Npd and NOFFSET,CQI for "periodic CSI reporting" of the TDD scell, according to one of Table 5, Table
6, and Table 7. Table which is to be used among Table 5, Table 6, and Table 7 may
be defined in a communication standard specification, or may be appointed through
signaling between the UE and the NB.
[0143] If the UE receives a value that is different from N
pd defined in the first to seventh embodiments, as a CSI transmission period of the
Scell, from the NB, the UE cannot perform "periodic CSI reporting" of the Scell.
[0144] It will be apparent to those skilled in the art that various modifications and variations
can be made in the present invention without departing from the scope of the invention.
Thus, it is intended that the present invention covers the modifications and variations
of this invention provided they come within the scope of the appended claims.